Modeling and nonlinear heading control of sailing yachts

This paper presents a study on the development and testing of a model-based heading controller for a sailing yacht. Using Fossen's compact notation for marine vehicles, we first describe a nonlinear four-degree-of-freedom (DOF) dynamic model for a sailing yacht, including roll. Our model also includes two possible steering mechanisms: a conventional rudder and a simple moving mass system. Starting from this model, we then design, for both steering mechanisms, a nonlinear heading controller using the integrator backstepping method, which exponentially stabilizes the heading/yaw dynamics. By computing the equilibrium points of the system, the course is related to the heading angle, and course control is also achieved. A few simulation results are presented to illustrate the behavior of our control designs.